The invention relates to electrical connectors, and more particularly, to multiconductor electrical connectors having a pair of mutually engageable elements which when brought together provide a plurality of electrical contacts. Such connectors are used to facilitate connection and disconnection of electronic units in a system of panel or rack-mounted equipment. Modern aircraft, for example, are equipped with such racks affixed to the aircraft structure. The racks are adapted to receive and support electronic units or boxes such as computers, radios, navigation units, flight control units, etc. When servicing is required, a unit may be removed from the rack and replaced by another. The disconnection and removal of one unit and the insertion and connection of another, in order to be quickly and efficiently accomplished, requires a durable electrical connector having one element mounted on the rack and wired to the permanent aircraft wiring bus, and a second element mounted on the electronic unit or box and wired to the circuits contained in the unit. Each connector element carries a plurality of electrical terminals adapted to engage a corresponding plurality of electrical terminals on the other element of the connector, when the elements are joined.
Prior art connector elements comprised a metal shell or frame inside which was bonded a plastic housing holding the electrical contacts. Prior to assembly, the metal shell required machining operations to provide tapped holes or holes receiving threaded inserts for fastening the connector element to a unit or to a rack assembly. The number of manufacturing operations, i.e., machining, assembly and loading, was labor-intensive and costly. Further, accumulation of tolerances during the multiple manufacturing and assembly steps limited control over the position of the electrical contacts held in the plastic body of the connector element.
Many remotely mounted electronic units require more than one connector assembly to provide a sufficient number of electrical connections to the aircraft wiring bus. The precise alignment of multiple connector elements is difficult, and in the prior art was accomplished by installing the connector elements loosely in the rack assembly or electronic unit as applicable with fasteners finger-tight, installing the electronic unit in the rack assembly and mating the connector elements to normalize their position, and finally securely tightening the fasteners. This method is time-consuming, labor-intensive and complicated by limited access to the connector fastening elements, especially in cramped environments such as in aircraft.
Remotely mounted electronic units perform a wide variety of functions. Industry standardization, particularly in avionics, has limited the shape and dimensions of electronics units or "black boxes" to a few standard sizes. This allows standardization of many parts including components of the rack assembly such as mounting trays. Therefore, many different black boxes could be potentially installed in the same mounting tray. This requires that a keying system be provided which allows only a specific type of remotely mounted unit or black box to be mated with a particular connector element in a mounting tray. Prior-art connectors utilized keys and keyways of various shapes adhesively bonded into the connector body or attached to the connector shell with threaded fasteners. Adhesively bonded keying elements, if damaged, were difficult if not impossible to remove and replace, and keying systems utilizing threaded fasteners were expensive to manufacture and install.
It is, therefore, an object of the present invention to provide an improved electrical connector.
It is another object of the present invention to provide an improved rack-mounted connector assembly having unitary connector elements.
Still another object of the invention is to provide an improved electrical connector assembly for rack-mounted equipment having unitary connector elements formed of durable thermoplastic material.
Another object of our invention is to provide an improved electrical connector having a novel keying system which is simply and easily assembled integrally with the connector mounting hardware.
In accordance with the present invention, there is provided a multiconductor electrical connector having a pair of mutually engageable connector elements, each of the elements being a unitary body molded from thermoplastic material. The connector includes fastener means for attaching at least one of the connector elements to a fixed structure and coaxial with the fastening means, means for keying the connector elements to one another. In one embodiment of the invention, an insulating panel grips a plurality of electrical conductor terminal pins associated with one of the connector elements, the panel being fastenable to the connector element thus facilitating easy removal and replacement of the one connector element.